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A systematic quantum chemical investigation of the CH bond activation in methane by gas phase vanadium oxide cation VO +
Author(s) -
Pykavy Mikhail,
Van Wüllen Christoph
Publication year - 2007
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20584
Subject(s) - chemistry , extrapolation , methane , basis set , endothermic process , molecule , quantum chemistry , computational chemistry , density functional theory , thermodynamics , physics , adsorption , mathematics , mathematical analysis , supramolecular chemistry , organic chemistry
The interaction between a methane molecule and the VO + cation in the gas phase has been investigated by means of single reference density functional (B3LYP) and wave function‐based multireference (MR) correlation calculations. For the latter, an extrapolation technique is used to evaluate correlation energies at the basis set limit. A comprehensive picture for the CH activation features a variety of molecular structures corresponding to both minima and transition states. Possible reaction paths are discussed, also taking into account change of the spin multiplicity. Activation of the methane molecule by VO + is always an endothermic process. Competing reaction paths might be expected. An evaluation of miscellaneous computational methods is performed using calculated energy differences for various molecular structures. Results obtained from the MR calculations exhibit no systematic convergence with increasing size of the active space used, and for two largest active spaces relative energies still differ by up to 25 kJ/mol. Simple mean difference between the B3LYP results and the best MR values is −50 ± 19 kJ/mol. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007